1. Field of the Invention
The present invention relates generally to telecommunications systems and services provided in an advanced intelligent network (xe2x80x9cAINxe2x80x9d) environment and more specifically to telecommunication systems for simultaneously ringing multiple subscriber lines when a single call is placed to a subscriber""s primary line.
2. Background of the Invention
Multiple communications systems have become ubiquitous in today""s society. It is not uncommon for individuals, referred to herein as xe2x80x9csubscribers,xe2x80x9d to have more than one telephone system including both wireline telephones and wireless telephones. Subscribers"" wireline telephones may or may not be co-located in the same building and the wireless telephones are, by design, highly mobile. This situation has resulted in a need for subscribers to maintain and distribute multiple telephone numbers which may be used to establish communication.
When a caller tries to reach a subscriber, the caller must dial the subscriber""s first telephone number and wait to see if anyone answers the call. If the call goes unanswered, the caller must try the next number and again wait for an answer. This process must be repeated until one of the calls is answered or the caller has tried all of the subscriber""s numbers without success. This situation can be frustrating for a caller because multiple telephone calls may have to be tried before successfully reaching the subscriber. Similarly, subscribers can be frustrated because the end result may be a missed call. Simultaneous ring services have been offered to solve this problem for subscribers having multiple telephone numbers.
In a simultaneous ring service, when a call is made to a subscriber""s wireline (xe2x80x9cprimary linexe2x80x9d) telephone number, the service provides a ringing tone on the primary line and on designated secondary lines. Such a service connects the caller to whichever telephone line is answered first. As known in the art, such simultaneous ring services may be extended to ring many different lines, wired or wireless, at the same time or to ring a series of lines in rapid succession. For simplicity, the description of conventional simultaneous ring services and the system and service of the present invention will be generally directed to simultaneous ringing of only two telephone lines. One of ordinary skill in the art will recognize how such services can be adapted to ring more than two lines simultaneously.
Although such simultaneous ring services have solved the subscribers"" problems, the implementation used in conventional services has resulted in further problems for the telephone service providers (xe2x80x9ctelcosxe2x80x9d). Conventional simultaneous ring services are implemented using a service node (xe2x80x9cSNxe2x80x9d) comprising the telco""s customer subscription data as described in more detail below.
Caller 110 in FIG. 1 is the person attempting to reach subscriber 112, a customer of telco 128. Caller 110 has telephone line 111. As known in the art, caller 110 could also be a customer of telco 128, or, caller 110 could be a foreign customer connecting through inter-exchange carrier (xe2x80x9cIXCxe2x80x9d) 114 as shown in FIG. 1. In the schematic diagram shown in FIG. 1, when caller 110 places a call to subscriber 112""s primary line (i.e., wireline 113) the call hits a termination attempt trigger (xe2x80x9cTATxe2x80x9d) on service switching point (xe2x80x9cSSPxe2x80x9d or xe2x80x9cswitchxe2x80x9d) 115. In response to this trigger, SSP 115 sends a query to service control point (xe2x80x9cSCPxe2x80x9d) 116 via signaling network 118. As known in the art, signaling network 118 is a packet switched network consisting of various network components, including, e.g., signaling transfer points (xe2x80x9cSTPsxe2x80x9d), SSPs, SCPs and the like. Common Channel Signaling System Number 7 (xe2x80x9cSS7xe2x80x9d) is a network protocol commonly used in signaling networks in North America, although other protocols may be implemented elsewhere or in the future. For the present invention, the specific signaling network protocol implemented is not important.
As known in the art, SCP 116 uses data stored in database 119 to formulate an appropriate answer to AIN queries it receives. Database 119 typically stores a plurality of records associated with each subscriber of the various services provided by the particular SCP. In the case of a conventional simultaneous ring service, database 119 includes the telephone numbers for the subscriber""s primary line and designated secondary lines, including wireless line 122. The database further includes information regarding the type of line used for each secondary line (i.e., whether the lines are wirelines or wireless lines). In response to the query from SSP 115, SCP 116 first checks database 119 to see if the calling party number corresponds to one of the subscriber""s designated secondary lines. If a match is made, SCP 116 instructs SSP 115 to continue with normal call processing, i.e., wireline 113 rings if it is available or caller 110 is provided a busy signal if wireline 113 is busy. If a match is not made, SCP 116 directs SSP 115 to forward the call to SN 124 for further call processing. As known in the art, SN 124 could be served by the same switch as the subscriber, or could be served by a different switch. In FIG. 1, SN 124 is served by a different switch, SSP 125, via PRI trunk 126.
As shown in FIG. 1, in conventional simultaneous ring services SN 124 uses database 127 to store a plurality of records associated with subscriber of the service. Just as with database 119 (on SCP 116) database 127 (on SN 124) stores telephone numbers for the subscriber""s primary and secondary lines and type information for the secondary lines. As described above, SSP 115 forwards the call the SN 124 for further call processing. SN 124 uses the subscriber""s primary line telephone number, contained in the redirecting party number field of the call setup message, to identify the subscriber being called. SN 124 looks up the subscriber""s secondary numbers in database 127 and initiates calls to each secondary number as well as to the primary number. SN 124 prioritizes and spaces these calls as necessary if any of the secondary lines are wireless lines. As soon as one of these calls is answered, SN 124 connects caller 110 to the answered line and ends the unanswered calls. As discussed above, this conventional simultaneous ring service provides the functionality needed from the subscriber""s and the caller""s point of view. However, the conventional implementation described above is not efficient for the telco providing the service.
As known in the art service nodes as very expensive systems and are generally for specific applications. If the load on a particular service node is heavy, multiple service nodes may be required to accommodate an application. Because conventional implementation requires subscription data to be stored on a service node, telco 128 must maintain multiple databases on multiple network nodes. Moreover, the information in these databases is duplicative of the information already needed to be stored in the service control point as described above. A need therefore exists for a more efficient system and method for providing simultaneous ring services for subscribers.
The present invention provides a system and method for providing simultaneous ringing on multiple subscriber telephone lines using a centralized database for storing the information related to the subscriber""s lines. The database is stored on a centralized AIN node, usually a service control point, and it includes the telephone numbers for a subscriber""s primary line and one or more secondary lines. When a caller places a call to the subscriber""s primary line, a trigger is encountered at the switch serving the subscriber""s primary line. In response to the trigger, the subscriber""s switch queries the service control point for call processing instructions. In response to this query, the service control point instructs the subscriber""s switch to forward the call to a service node. In one embodiment, the service control inserts a code indicating the quantity of wireless lines and the total quantity of secondary lines designated by the subscriber. When the service node receives the forwarded call, it initiates a series of outbound calls to the subscriber""s primary and secondary lines as described below.
Because the service node in the present invention does not have any local subscription data, it relies on the service control point to provide the information from its centralized database. To accomplish this, the service node places a call to the subscriber""s primary line number, which it retrieves from the information provided within the original forwarded call. In placing this call, the service node inserts a special identification code into the redirecting party number field of the call setup message. This identification code is used to indicate which of the subscriber""s designated telephone number is being requested, i.e., whether the first, second, third, etc. telephone number is needed. In one embodiment of the present invention, the switch serving the service node is provisioned with an appropriate trigger that temporarily suspends this call while the switch queries the service control point for call processing instructions. In a second embodiment of the present invention, the trigger on the subscriber""s line is used to initiate the query.
The service control point uses the subscriber""s primary telephone number (found in the called party number field) and the identification code (found in the redirecting party number field) to retrieve the corresponding secondary telephone number from its database. In one embodiment, the service control point provides telephone numbers corresponding to wireless secondary lines prior to providing wireline numbers. In this manner, the service node spaces the calls out to ensure proper timing for the calls as described in more detail below.
The service control point inserts the retrieved secondary telephone number into the called party number field and instructs the switch to continue call processing using the telephone number provided. The service node repeats these steps for each telephone number in the subscriber""s designated list of lines to ring via this service. If one of the called lines is answered, the service node drops the other calls and stops initiating new calls. The caller is then connected to the answered call. If none of the called lines are answered, the service node drops all of the calls. In one embodiment of the present invention, the service node provides an appropriate announcement to the caller.
In one embodiment of the present invention, the simultaneous ringing service performs many additional functions such as checking the status of each line prior to placing the simultaneous calls, or checking to see if the calling party number is one of the subscriber""s designated lines. Further, the service can provide an administration system that allows subscribers to change the status of their subscription and to add or delete lines from the database. Finally, in one embodiment of the present invention, a heartbeat call from the service node to the service control point is provided for tracking the availability of the service node for processing simultaneous ring services.